//-----------------------------------------------------------------------------
//
// Copyright (c) Microsoft. All rights reserved.
// This code is licensed under the Microsoft Public License.
// THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
// IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
// PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
//
//-----------------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;

namespace Microsoft.Cci.Pdb
{
    internal class PdbFunction
    {
        static internal readonly Guid msilMetaData = new Guid(0xc6ea3fc9, 0x59b3, 0x49d6, 0xbc, 0x25,
                                                            0x09, 0x02, 0xbb, 0xab, 0xb4, 0x60);
        static internal readonly IComparer byAddress = new PdbFunctionsByAddress();
        static internal readonly IComparer byAddressAndToken = new PdbFunctionsByAddressAndToken();
        //static internal readonly IComparer byToken = new PdbFunctionsByToken();

        internal uint token;
        internal uint slotToken;
        //internal string name;
        //internal string module;
        //internal ushort flags;

        internal uint segment;
        internal uint address;
        //internal uint length;

        //internal byte[] metadata;
        internal PdbScope[] scopes;
        internal PdbSlot[] slots;
        internal PdbConstant[] constants;
        internal string[] usedNamespaces;
        internal PdbLines[] lines;
        internal ushort[]/*?*/ usingCounts;
        internal IEnumerable<INamespaceScope>/*?*/ namespaceScopes;
        internal string/*?*/ iteratorClass;
        internal List<ILocalScope>/*?*/ iteratorScopes;

        private static string StripNamespace(string module)
        {
            int li = module.LastIndexOf('.');
            if (li > 0)
            {
                return module.Substring(li + 1);
            }
            return module;
        }


        internal static PdbFunction[] LoadManagedFunctions(/*string module,*/
                                                           BitAccess bits, uint limit,
                                                           bool readStrings)
        {
            //string mod = StripNamespace(module);
            int begin = bits.Position;
            int count = 0;

            while (bits.Position < limit)
            {
                ushort siz;
                ushort rec;

                bits.ReadUInt16(out siz);
                int star = bits.Position;
                int stop = bits.Position + siz;
                bits.Position = star;
                bits.ReadUInt16(out rec);

                switch ((SYM)rec)
                {
                    case SYM.S_GMANPROC:
                    case SYM.S_LMANPROC:
                        ManProcSym proc;
                        bits.ReadUInt32(out proc.parent);
                        bits.ReadUInt32(out proc.end);
                        bits.Position = (int)proc.end;
                        count++;
                        break;

                    case SYM.S_END:
                        bits.Position = stop;
                        break;

                    default:
                        //Console.WriteLine("{0,6}: {1:x2} {2}",
                        //                  bits.Position, rec, (SYM)rec);
                        bits.Position = stop;
                        break;
                }
            }
            if (count == 0)
            {
                return null;
            }

            bits.Position = begin;
            PdbFunction[] funcs = new PdbFunction[count];
            int func = 0;

            while (bits.Position < limit)
            {
                ushort siz;
                ushort rec;

                bits.ReadUInt16(out siz);
                int star = bits.Position;
                int stop = bits.Position + siz;
                bits.ReadUInt16(out rec);

                switch ((SYM)rec)
                {

                    case SYM.S_GMANPROC:
                    case SYM.S_LMANPROC:
                        ManProcSym proc;
                        //int offset = bits.Position;

                        bits.ReadUInt32(out proc.parent);
                        bits.ReadUInt32(out proc.end);
                        bits.ReadUInt32(out proc.next);
                        bits.ReadUInt32(out proc.len);
                        bits.ReadUInt32(out proc.dbgStart);
                        bits.ReadUInt32(out proc.dbgEnd);
                        bits.ReadUInt32(out proc.token);
                        bits.ReadUInt32(out proc.off);
                        bits.ReadUInt16(out proc.seg);
                        bits.ReadUInt8(out proc.flags);
                        bits.ReadUInt16(out proc.retReg);
                        if (readStrings)
                        {
                            bits.ReadCString(out proc.name);
                        }
                        else
                        {
                            bits.SkipCString(out proc.name);
                        }
                        //Console.WriteLine("token={0:X8} [{1}::{2}]", proc.token, module, proc.name);

                        bits.Position = stop;
                        funcs[func++] = new PdbFunction(/*module,*/ proc, bits);
                        break;

                    default:
                        {
                            //throw new PdbDebugException("Unknown SYMREC {0}", (SYM)rec);
                            bits.Position = stop;
                            break;
                        }
                }
            }
            return funcs;
        }

        internal static void CountScopesAndSlots(BitAccess bits, uint limit,
                                                 out int constants, out int scopes, out int slots, out int usedNamespaces)
        {
            int pos = bits.Position;
            BlockSym32 block;
            constants = 0;
            slots = 0;
            scopes = 0;
            usedNamespaces = 0;

            while (bits.Position < limit)
            {
                ushort siz;
                ushort rec;

                bits.ReadUInt16(out siz);
                int star = bits.Position;
                int stop = bits.Position + siz;
                bits.Position = star;
                bits.ReadUInt16(out rec);

                switch ((SYM)rec)
                {
                    case SYM.S_BLOCK32:
                        {
                            bits.ReadUInt32(out block.parent);
                            bits.ReadUInt32(out block.end);

                            scopes++;
                            bits.Position = (int)block.end;
                            break;
                        }

                    case SYM.S_MANSLOT:
                        slots++;
                        bits.Position = stop;
                        break;

                    case SYM.S_UNAMESPACE:
                        usedNamespaces++;
                        bits.Position = stop;
                        break;

                    case SYM.S_MANCONSTANT:
                        constants++;
                        bits.Position = stop;
                        break;

                    default:
                        bits.Position = stop;
                        break;
                }
            }
            bits.Position = pos;
        }

        internal PdbFunction()
        {
        }

        internal PdbFunction(/*string module, */ManProcSym proc, BitAccess bits)
        {
            this.token = proc.token;
            //this.module = module;
            //this.name = proc.name;
            //this.flags = proc.flags;
            this.segment = proc.seg;
            this.address = proc.off;
            //this.length = proc.len;

            if (proc.seg != 1)
            {
                throw new PdbDebugException("Segment is {0}, not 1.", proc.seg);
            }
            if (proc.parent != 0 || proc.next != 0)
            {
                throw new PdbDebugException("Warning parent={0}, next={1}",
                                            proc.parent, proc.next);
            }
            //if (proc.dbgStart != 0 || proc.dbgEnd != 0) {
            //  throw new PdbDebugException("Warning DBG start={0}, end={1}",
            //                              proc.dbgStart, proc.dbgEnd);
            //}

            int constantCount;
            int scopeCount;
            int slotCount;
            int usedNamespacesCount;
            CountScopesAndSlots(bits, proc.end, out constantCount, out scopeCount, out slotCount, out usedNamespacesCount);
            int scope = constantCount > 0 || slotCount > 0 || usedNamespacesCount > 0 ? 1 : 0;
            int slot = 0;
            int constant = 0;
            int usedNs = 0;
            scopes = new PdbScope[scopeCount + scope];
            slots = new PdbSlot[slotCount];
            constants = new PdbConstant[constantCount];
            usedNamespaces = new string[usedNamespacesCount];

            if (scope > 0)
                scopes[0] = new PdbScope(this.address, proc.len, slots, constants, usedNamespaces);

            while (bits.Position < proc.end)
            {
                ushort siz;
                ushort rec;

                bits.ReadUInt16(out siz);
                int star = bits.Position;
                int stop = bits.Position + siz;
                bits.Position = star;
                bits.ReadUInt16(out rec);

                switch ((SYM)rec)
                {
                    case SYM.S_OEM:
                        {          // 0x0404
                            OemSymbol oem;

                            bits.ReadGuid(out oem.idOem);
                            bits.ReadUInt32(out oem.typind);
                            // internal byte[]   rgl;        // user data, force 4-byte alignment

                            if (oem.idOem == msilMetaData)
                            {
                                string name = bits.ReadString();
                                if (name == "MD2")
                                {
                                    byte version;
                                    bits.ReadUInt8(out version);
                                    if (version == 4)
                                    {
                                        byte count;
                                        bits.ReadUInt8(out count);
                                        bits.Align(4);
                                        while (count-- > 0)
                                            this.ReadCustomMetadata(bits);
                                    }
                                }
                                bits.Position = stop;
                                break;
                            }
                            else
                            {
                                throw new PdbDebugException("OEM section: guid={0} ti={1}",
                                                            oem.idOem, oem.typind);
                                // bits.Position = stop;
                            }
                        }

                    case SYM.S_BLOCK32:
                        {
                            BlockSym32 block = new BlockSym32();

                            bits.ReadUInt32(out block.parent);
                            bits.ReadUInt32(out block.end);
                            bits.ReadUInt32(out block.len);
                            bits.ReadUInt32(out block.off);
                            bits.ReadUInt16(out block.seg);
                            bits.SkipCString(out block.name);
                            bits.Position = stop;

                            scopes[scope++] = new PdbScope(this.address, block, bits, out slotToken);
                            bits.Position = (int)block.end;
                            break;
                        }

                    case SYM.S_MANSLOT:
                        uint typind;
                        slots[slot++] = new PdbSlot(bits, out typind);
                        bits.Position = stop;
                        break;

                    case SYM.S_MANCONSTANT:
                        constants[constant++] = new PdbConstant(bits);
                        bits.Position = stop;
                        break;

                    case SYM.S_UNAMESPACE:
                        bits.ReadCString(out usedNamespaces[usedNs++]);
                        bits.Position = stop;
                        break;

                    case SYM.S_END:
                        bits.Position = stop;
                        break;

                    default:
                        {
                            //throw new PdbDebugException("Unknown SYM: {0}", (SYM)rec);
                            bits.Position = stop;
                            break;
                        }
                }
            }

            if (bits.Position != proc.end)
            {
                throw new PdbDebugException("Not at S_END");
            }

            ushort esiz;
            ushort erec;
            bits.ReadUInt16(out esiz);
            bits.ReadUInt16(out erec);

            if (erec != (ushort)SYM.S_END)
            {
                throw new PdbDebugException("Missing S_END");
            }
        }

        private void ReadCustomMetadata(BitAccess bits)
        {
            int savedPosition = bits.Position;
            byte version;
            bits.ReadUInt8(out version);
            if (version != 4)
            {
                throw new PdbDebugException("Unknown custom metadata item version: {0}", version);
            }
            byte kind;
            bits.ReadUInt8(out kind);
            bits.Align(4);
            uint numberOfBytesInItem;
            bits.ReadUInt32(out numberOfBytesInItem);
            switch (kind)
            {
                case 0: this.ReadUsingInfo(bits); break;
                case 1: break; // this.ReadForwardInfo(bits); break;
                case 2: break; // this.ReadForwardedToModuleInfo(bits); break;
                case 3: this.ReadIteratorLocals(bits); break;
                case 4: this.ReadForwardIterator(bits); break;
                case 5: break;
                case 6: break; //vs2015 thing
                case 7: break; //vs2015 thing
                default:
                    throw new PdbDebugException("Unknown custom metadata item kind: {0}", kind);
            }
            bits.Position = savedPosition + (int)numberOfBytesInItem;
        }

        private void ReadForwardIterator(BitAccess bits)
        {
            this.iteratorClass = bits.ReadString();
        }

        private void ReadIteratorLocals(BitAccess bits)
        {
            uint numberOfLocals;
            bits.ReadUInt32(out numberOfLocals);
            this.iteratorScopes = new List<ILocalScope>((int)numberOfLocals);
            while (numberOfLocals-- > 0)
            {
                uint ilStartOffset;
                uint ilEndOffset;
                bits.ReadUInt32(out ilStartOffset);
                bits.ReadUInt32(out ilEndOffset);
                this.iteratorScopes.Add(new PdbIteratorScope(ilStartOffset, ilEndOffset - ilStartOffset));
            }
        }

        //private void ReadForwardedToModuleInfo(BitAccess bits) {
        //}

        //private void ReadForwardInfo(BitAccess bits) {
        //}

        private void ReadUsingInfo(BitAccess bits)
        {
            ushort numberOfNamespaces;
            bits.ReadUInt16(out numberOfNamespaces);
            this.usingCounts = new ushort[numberOfNamespaces];
            for (ushort i = 0; i < numberOfNamespaces; i++)
            {
                bits.ReadUInt16(out this.usingCounts[i]);
            }
        }

        internal class PdbFunctionsByAddress : IComparer
        {
            public int Compare(Object x, Object y)
            {
                PdbFunction fx = (PdbFunction)x;
                PdbFunction fy = (PdbFunction)y;

                if (fx.segment < fy.segment)
                {
                    return -1;
                }
                else if (fx.segment > fy.segment)
                {
                    return 1;
                }
                else if (fx.address < fy.address)
                {
                    return -1;
                }
                else if (fx.address > fy.address)
                {
                    return 1;
                }
                else
                {
                    return 0;
                }
            }
        }

        internal class PdbFunctionsByAddressAndToken : IComparer
        {
            public int Compare(Object x, Object y)
            {
                PdbFunction fx = (PdbFunction)x;
                PdbFunction fy = (PdbFunction)y;

                if (fx.segment < fy.segment)
                {
                    return -1;
                }
                else if (fx.segment > fy.segment)
                {
                    return 1;
                }
                else if (fx.address < fy.address)
                {
                    return -1;
                }
                else if (fx.address > fy.address)
                {
                    return 1;
                }
                else
                {
                    if (fx.token < fy.token)
                        return -1;
                    else if (fx.token > fy.token)
                        return 1;
                    else
                        return 0;
                }
            }
        }

        //internal class PdbFunctionsByToken : IComparer {
        //  public int Compare(Object x, Object y) {
        //    PdbFunction fx = (PdbFunction)x;
        //    PdbFunction fy = (PdbFunction)y;

        //    if (fx.token < fy.token) {
        //      return -1;
        //    } else if (fx.token > fy.token) {
        //      return 1;
        //    } else {
        //      return 0;
        //    }
        //  }

        //}
    }
}
